Photoelectrostatic copying machine

ABSTRACT

This invention concerns an automatic copying machine operable between a reduced copying mode and a full size copying mode. It has a turret lens assembly movable between different positions for projecting a full size or a reduced size image of an original onto a copy sheet, and a drive system for moving the original and copy sheet respectively past illuminating and exposure stations at equal or unequal speeds. A resilient overtravel operating assembly moves the lens assembly between positions and firmly holds it in place. In the full size copying mode the copy sheet and original move at the same speed; in the reduced copying mode the original moves faster than the copy sheet and in proportion to the size of the reduced light image. A single switch controls the copying mode. During the reduced copying mode, it turns on edge exposure lamps which discharge unexposed marginal areas which would otherwise form dirty copy sheet edges.

United States Patent [191 Lux et al.

MACHINE 1 Jan. 2, 1973 Primary Examiner-Joseph Wegbreit Attorney-Mason; Kolehmainen, Rathburn & Wyss [75] Inventors: George K. Lux, San Jose, Calif.; James B. Ellls Chicago; John J. Schulze, Prospect Heights, both of [57] ABSTRACT Ill. This invention concerns an automatic copying machine operable between a reduced copying mode [73] Asslgnee lz mntg g and a full size copying mode. It has a turret lens as- I pe sembly movable between different positions for pro- [22] Filed: Feb. 10, 1970 jecting a full size or a reduced size image of an original onto a copy sheet, and a drive system for [21] Appl 14886 moving the original and copy sheet respectively past Related s Application Data illuminating and exposure stations at equal or unequal 62 p f speeds. A resilient overtravel operating assembly 1V1S101l 0 Ser. No. 699,507, Jan. 22, 1968, Pat. No. moves the lens assembly between posmons and firmly holds it in place. In the full size copying mode the copy sheet and original move at the same speed; in the Elks}? reduced copying mode the original moves faster than o "I t e py sh e d in proportion to the Size f h Fleld 0 Search ..355/50, 52, reduced image. A single switch controls the copying mode. During the reduced copying mode, it [56] Reierences Cited turns on edge exposure lamps which discharge unex- UNITED STATES PATENTS gtfied margtina: eaireas which would otherwise form 1 co ys ee ges. 2,462,439 2/1949 Thompson ..27l/74 X y p 3,354,777 11/1967 Normandy et a1. ..355/ X 5 Claims, 4 Drawing Figures 16? 10s 9 [16 J6 a? 185 2; 98 $0 32 20 4/6 32a v. I I! a 0 M 31 86 L 100 f." 7 7 J J00: r 9? 66 4/ F P N 9 ea 44 66 62 J0 t bflae 30 34a 6'4 Pmmmm 2 ma SHEET 1 BF 3 .za c Ellis Geo Ja J0 PKTENT'EDJ 2 ms SHEET 2 OF 3 Lax Ellis J Scfialge,

bm ww 121 827 or George James (Io/212 $6M- "Ju- PHOTOELECTROSTATIC COPYING MACHINE This application is a division of copending application Ser. No. 699,507,fi led Jan. 2, 1968, now U. S.

Pat. No. 3,556,655, dated Jan. 19, 1971.

The present invention relates to a photoelectrostatic copying machine and has for a primary object the provision of an improved copying machine capable of automatically producing both full size and reduced size copies of an original.

Various types of automatic copy making machines for producing copies of graphic originals on photoconductive material are known. In such machines, the photoconductive material may comprise a coating on a paper copy sheet or a layer of photoconductive material on a metal member such as a drum. In an automatic copy making operation a graphic original such as an original sheet is moved past a light source, and a light image corresponding to the graphic image is projected through an optics, assembly onto a moving photoconductive member. Prior to exposure, the photoconductive surfaceof the member is charged, and when the surface is struck by light reflected from the original, the charge is selectively dissipated to form a pattern of charged and discharged areas corresponding to the original image. This charge image is then developed by the application of a suitable developer material such as a finely divided powder and thedeveloped image, in the case of a photoconductive copy sheet, is rendered permanent by suitable fusing or fixing apparatus. In the case of a metal drum, the powder image may be transferred to a paper sheet and then bonded to the sheet. One example of an automatic copy making machine of this type can be found in the co-pending application of John L. Tregay and Kristian L. Helland, Ser. No. 389,037, filed Aug. 12, 1964, now US. Pat. No. 3,556,655, dated Jan. 19,1971.

Although most copying machines produce a copy substantially equal in size to the original, machines have been developed for producing copies of reduced size. In such machines, the optics assembly is designed so that the reflected light image projected upon the photoconductive member is smaller than the original image. In addition, if themachine is of the type wherein both the original and the photoconductive member are moved during the illumination-exposure process, the original is moved faster than the photoconductive member at a predetermined speed. One example of a machine for producing areduced size copy may be found'in the co-pending application of Daniel B. Granzow, George K. Lux, and Stanley A. Gawron, Ser. No. 440,178, filed Mar. 16, 1965, now US. Pat. No. 3,388,644, dated June 18, 1968.

Although the machines described in the above identified co-pending applications have'proven to be highly satisfactory for their intended uses, it is an important object of the present invention to provide an improved automatic copying machine capable not only of producing copies equal in size to the original but also capable of producing copies differing in size from the original.

Another object is to provide a machine including a single control means for automatically conditioning the A further object is to provide a novel control arrangement for simultaneously controlling the lens assembly and the drive system of an automatic copying machine for producing both full size and reduced size copies of an original.

Another object is to provide novel apparatus for preventing the adherence of developer material to marginal regions of a photoconductive member when reduced size copies are made.

Still a further object is to provide a compact and versatile copying machine for making different size copies of an original which has an optical path between the illuminating and exposure stations of a fixed length, thus obviating the need to movably mount the stations.

of the present invention are realized in one embodiment of the invention by the provision of a copy making machine including a drive system for moving an original sheet past a fixed illumination station and simultaneously moving a copy sheet past a fixed expo,- sure station. A light source at the illumination station illuminates the original to produce a light image which is projected along an optical path of a fixed length onto the copy sheet at the exposure station by means of an optics assembly including an adjustable lens assembly. In accordance with one important feature of the invention, both the drive assembly and the adjustable lens assembly are operated by a single control means between one condition wherein the copy produced is equal in size to the original and another condition wherein a reduced size copy is produced.

In accordance with another feature of the invention a novel drive system is provided for propelling the original and the copy sheet through the machine at equal or.unequal speeds. A main drive motor is coupled to drive rollers which propel the copy sheet past the exposure station, and these drive rollers are operated continuously. During the operation of producing a copy sheet equal in size to the original, a first coupling means serves to rotate the original sheet drive rollers at the same speed as the copy sheet drive rollers. However, when a reduction mode of operation is selected, the first coupling means is automatically disengaged and a second coupling means together with a speed reduction assembly is used to operate the original sheet drive rollers at a faster speed than the copy sheet drive rollers and in proportion to the reduced light image. For example, if the reduced light image is 30 percent smaller than the original, the original is moved 30 percent faster than the copy sheet. Both coupling means are disengaged and a brake is engaged in order to stop the original drive rollers while the copy sheet drive rollers continue rotating.

In order to prevent dark marginal areas on the copy sheet which might otherwise be produced during reduced size copy making operations, a light source is positioned adjacent the exposure area for illuminating the outer edges of the copy sheet thereby to dissipate all charge thereon and to prevent the adherence of developer powder to these regions.

The invention, together with the above and other objects and advantages thereof, will best be understood from considering the following detailed description of one embodiment, in the course of which reference is made to the accompanying drawings, in which:

In brief, the above and other objects and advantages.

FIG. 1 is a fragmentary plan view of a portion of a copying machine constructed in accordance with the present invention, and illustrating the illuminating station, exposure station and drive system of the machine;

FIG. 2 is an elevational view of the optics assembly of the machine, and illustrating the adjustable lens assembly in simplified form;

, FIG. 3 is an enlarged, fragmentary, top view of the drive system of the machine shown partly in section;

FIG. 4 is a schematic diagram of part of a circuit for controlling the operation of the machine.

Having reference now to the drawings, there are illustrated several portions of a photoelectrostatic automatic copying machine operable, in accordance with the present invention, to produce copies equal in size to a graphic original, or alternatively to produce reduced size copies. Many portions of the machine of the present invention, including those portions not illustrated in the drawings, may be similar to the machine described in the above mentioned co-pending application of John L. Tregay et al., and reference may be had to that application for an understanding of portions of the machine not here illustrated or described in detail.

In general, the machine serves to produce copies on photoconductive copy' sheets of graphic original images carried on original sheets. The machine includes an illumination station generally designated as 20 (FIG. 1) where a moving original sheet is illuminated, as well as an exposure station generally designated as 22 where a charged, photoconductive copy sheet is exposed by a light image reflected from the original. An optics assembly generally designated as 24 (FIG. 2) including an adjustable lens assembly generally designated as 26 (FIGS. 2) projects a reflected light image from the illuminated original sheet at the illumination station 20 onto the charged surface of the copy sheet at theexposure station 22. A drive system designated as a whole by the reference numeral 28 (FIGS. 1 and 3) serves simultaneously to propel the original sheet past the illumination station 20 and to propel the copy sheet past the exposure station 22.

In order to propel the original and copy sheets past the illumination and exposure stations 20 and 22, the drive system 28 includes original sheet drive rollers 30 and 32 located near the forwardand rear edges ofthe illumination station 20, and a pair of copy sheet drive rollers 34 and 36 located near the forward and rear edges of the exposure station 22. Each drive roller is normally in contact with a corresponding idler roller (not shown) so that copy and original sheets are advanced by the drive rollers past the exposure station 22 and the illumination station 20, respectively.

When it is desired to make a copy, an original sheet is fed into the machine and'is guided by suitable guide means (not shown) toward the illumination station 20. When the leading edge of the original reaches the drive rollers 30 at the entry end of the illumination station 20, it operates an original sheet sensing switch 38. As described in more detail hereinafter, operation of the original switch 38 by an original sheet causes the original sheet to be held stationary with its leading edge at the original drive roller 30 while a copy sheet is automatically advanced toward the exposure station 22 from a roll or stack in a copy sheet storage and supply enclosure (not shown).

A copy sheet entering the machine is moved by suitable drive and guide means (not shown) toward the illumination station. When the leading edge of the copy sheet reaches the copy sheet drive roller 34 at the entry .end of the exposure station, the sheet operates a copy sheet sensing switch 40. In a manner described in more detail hereinafter, operation of the switch 40 by 'the copy sheet causes the copy sheet to be advanced past the exposure station 22 while the original sheet is advanced past the illumination station 20.

As described in considerably more detail in the above identified co-pending application of John L. Tregay et al., the copy sheet as it moves into the exposure station 22 is charged by means of a corona discharge assembly (FIG. 1) including a corona discharge wire 41 which deposits a charge on the photoconductive surface of the copy sheet. The exposure station is defined by a horizontally disposed plate or housing 42 having an aperture 44 therein through which reflected light is projected by the optics assembly 24 against the charged surface of the copy sheet. Suitable guiding means in the form of a taut wire 46 supports the copy sheet as it moves past the corona discharge wire 40 and the aperture 44.

The illumination station 20 is defined by a plate or housing 48 having an aperture 50 preferably closed by a transparent glass plate 52. As the original sheet moves across the glass plate 52, it is illuminated by means of a lamp 54 (FIGS. 1, 2, and 4), and a reflected light image is projected by the optics assembly 24 and adjustable lens assembly 26 onto the moving surface of the copy sheet through the aperture 44 at the exposure station 22.

As will be readily understood by those skilled in the art, illumination of the charged copy sheet results in selective dissipation of the charge in regions struck by light, so that there is produced on the surface of the sheet a charge pattern or image corresponding to the reflected light image. This charge .image may be developed in any suitable fashion as by the application of a finely divided developer powder, and the developed powder image may be rendered permanent by fusing or fixing, as described in the above identified co-pending application of John L. Tregay, et al.

In accordance with a primary object of the present invention, the machine is capable not only of producing copies equal in size to the original but is also capable of producing copies of a reduced size. When a full size copy is produced, the'reflected light image striking the copy sheet at the exposure station is equal insize to the graphic original image on the original sheet. Since both the original sheet and the copy sheet are moving during the illumination and exposure process, and since the reflected light image and the original image are equal in size, it is necessary for the original sheet and the copy sheet to move at the same speed through the illumination station 20 and the exposurest'ation 22. However, when a reduced size copy is made, the reflected light image projected onto the copy sheet is smaller insize than the original image on the original sheet. Accordingly, in order to produce a reduced size copy, adjustment of the lens assembly 26 of the optics assembly 24 is required. In addition, since thereflected image is smaller than the original image, it is necessary for the original sheet to move past the illumination station 20 faster than the copy sheet moves past the exposure station 22, but at a predetermined speed. Furthermore, in order to center the reduced copy on the copy sheet it is desirable for the copy sheet to enter the exposure station before the original enters the illumination station.

, In accordance with important features of the present invention, there are provided both the novel adjustable lens assembly 26 for automatically changing the size of the projected light image relative to the size of the original image, and also the novel drive system 28 capable of automatically moving the original and copy sheet either at the same speed or at different speeds. In addition, in accordance with a feature of the invention, there is provided means including a control circuit 56 (FIG. 8) controlling both the lens assembly 26 and the drive system 28 for automatically conditioning the machine for either full size or reduced size copy making operations in response to the operation of a single selector switch 58.

Proceeding now to a description of the drive system 28 (FIGS. 1 and 3) the system 28 may be conditioned to operate the original drive rollers 30 and 32 and the copy sheet drive rollers 34 and 36 at equal or unequal speeds, and to stop the original drive rollers 30 and 32 while the copy sheet drive rollers continue to rotate. In one mode of operation, when full size copies are made, a first electric clutch generally designated as 60 is energized while a second clutch generally designated as 62 and an electric brake generally designated as 64 are deenergized. In this mode of operation the original sheet is propelled past the illumination station at the same rate of speed that the copy sheet is propelled past the exposure station 22. In a second mode of operation, the clutch 62 is energized while the clutch 60 and the brake 64 are de-energized. In this mode of operation, which is utilized during the reduced size copy making process, a speed reduction assembly generally designated as 66 is coupledbetween the copy sheet and the original drive rollers and the original sheet is propelled past the illumination station 20 faster than the copy sheet is propelled past the exposure station 22. Q

In a third mode of operation the brake 64 is energized while-the clutches 60 and 62 are de-energized. This mode of operation is used while the original sheet is held stationary and the copy sheet is being advanced from the copy sheet supply enclosure, and also in the reduction process in' order to center the copy on the copy sheet. In this mode, the copy sheet drive rollers 34 and 36 continue to rotate while the original sheet drive rollers 30 and 32 are held'stationaryf More specifically, the sheet drive rollers 30, 32, 34, and 36 are secured respectively to shafts 30a, 32a, 34a, and 36a all of equal diameter and rotatably supported in a plurality of bearing assemblies 68 carried by fixed plates or walls 70, 72, 74, and 76 of the machine (see FIGS. 1 and 3). A main drive motor 78 (FIG. 8) operates continuously when the machine is on and continuously rotates the shaft 36a and the roller 36 by means of a chain and sprocket driveconnection 80 (FIG. 1 The rollers 34 and 36 and shafts 34a and 36a are constrained to rotateat the samespeed by means of a belt 82 running on a pair of pulleys 84 and 86 supported on the shafts 34a and 36a, and when the machine is on, the copy sheet drive rollers 34 and 36 operate continuously at a predetermined speed.

In order to rotate the original sheet drive rollers at the same speed as the copy sheet drive rollers during full size copying operations the clutch 60 coupled between the shafts 32a and 36a is energized, and the roller 32 is rotated at the same speed as the roller 36. The roller 30 and the shaft 30a are constrained to rotate at the same speed as the roller 32 and shaft 32a by means of a belt 88 running on pulleys 90 and 92 supported respectively on the shafts 30a and 32a.

In order to rotate the original sheet drive rollers 30 and 32 at a faster speed than the copy sheet drive rollers 34 and 36 during the process of making reduced size copies, the speed reduction assembly 66 is coupled between the rollers 36 and 30 by energization of the clutch 62. The speed reduction assembly 66 includes a speed reduction shaft 94 supported in one of the bearings 68 on the plate 74. The shaft 94 is constantly rotated by means of a belt 96 supported on a pair of pulleys 98 and 100 mounted respectively upon the shafts 36a and 94. The difference in angular velocity between these two shafts is determined by the difference in radius of the pulleys 98 and 100, this difference being chosen in accordance with the degree of size reduction desired in the reduced copy operating mode.

The electrically operated clutches 60 and 62 may be of any known construction, and are illustrated as including a pair of clutch plates 101 and 102 together with an operating winding 104 for magnetically causing the plates frictionally to engage one another upon energization of the winding. In the case of the clutch 60, the plate 101 is fixed to the continuously rotating shaft 36a while the plate 102 is fixed to the roller 32. Thus, upon energization of the winding 104 of clutch 60, the roller 32 rotates with the shaft 36a. Similarly, in the case of the clutch 62, the plate 101 is fixed to the continuously rotating shaft 94 while the plate 102 is fixed to the roller 30. Energization of the winding 104 of clutch 62 causes the roller 30 to rotate with the shaft 94.

As noted above, the novel drive system 28 also serves to stop the original drive rollers 30 and 32 while the copy sheet drive rollers 34 and 36 continue to rotate. This is accomplished by energization of the electric brake assembly 64 coupled between the fixed support plate 76 and the shaft 30a. The brake 64 includes a fixed plate 108 as well as a normally movable plate 1 10. Energization of a winding-112 ofthe brake causes the plate to engage the plate 108 so that the shaft 30a, together with the rollers 30, shaft 32a and roller 32, are prevented fromrotating. In the reduction mode of operation, the reflected light image from the original is of reduced size and is confined to a central portion of the photoconductive, charged copy sheet passing the exposure station 22. As a result, the edge portions of the sheet are not completely exposed and in these regions the charge is not fully dissipated. In subsequent developing and fixing operations, developer powder may adhere to these edge portions and produce dark or dirty" edge areas.

In order to overcome this problem and in accordance with a feature of the invention, there is provided a novel edge exposure assembly generally designated as 182 (FIG. 1) for fully exposing the edge regions of the copy sheet. Assembly 182 includes a masking plate 184 over which the exposed copy sheet passes after leaving the exposure station 22. The plate 184 includes a pair of apertures or slots 186 beneath which are disposed a pair of exposure lamps 188 and 190. As will appear hereinafter, the lamps 188 and 190 are normally deenergized, but are automatically energized when the machine is conditioned for reduced size copy making operations. The lamps serve completely to expose or burn out the edge portions of the sheet so that the adherence of developer material to these regions is prevented.

Proceeding now to a description of the control circuit 56 (FIG. 4) for controlling the operation of the automatic copy making machine, the circuit includes the single selector switch 58 for conditioning the machine either to produce full size or reduced size copies of the original. Operation of the switch 58, which may be a manually operated switch conveniently disposed at the front of the machine, is effective to control the drive system 28 to propel the original and copy sheet at either the same or at different speeds and to center the reduced copy on the copy sheet when reduced size copies are made. Furthermore, operation of the switch 58 controls the adjustable lens assembly 26 in order to project either a full size or a reduced size reflected light image onto the copy sheet. In addition, operation of the switch 58 controls the energization of the edge exposure lamps 188 and 190 in order to prevent the adherence of developer powder to the edges of the copy sheet in the reduction mode of operation.

The control circuit 56 may be supplied with power through a plug connector (not shown) and includes a common input terminal 200 and a nominal 1 volt AC input terminal 202, these being connected to a full wave rectifier bridge 204 used to provide a DC potential difference across a pair of DC power busses 206 and 208. The main drive motor 78 and the exposure lamp 54 are supplied from a nominal 230 volt AC input terminal 209.

As shown in FIG. 4, the control circuit 56 of the machine is in the standby condition ready to produce full size copies of originals fed to the machine. The selector switch 58 is open i.e., in the position for making full size copies, and the main drive motor 78 is energized. The electric clutch 60 is energized by a circuit including the original sheet sensing switch 38, and as a result the original sheet drive rollers'30 and 32 and the copy sheet drive rollers 34 and 36 'all rotate at the same speed.

The operation of making a full size copy of the original is begun by inserting an original sheet into the machine and the entire copy making process is completed automatically, after which the machine returns to the illustrated standby condition. When the leading edge of an original operates the original sheet When the leading edge of the copy'sheet reaches the copy sheet sensing switch 40, the original and copy sheet are advanced in synchronism past the illumination station 20 and the exposure station 22, the exposure lamp 54 is energized and the copy sheet supply clutch 21 1 is de-energized until the next copying operation. When the switch 40 closes, a circuit is completed for energizing a lamp relay 212, a relay 214 and a relay 216. A normally open set of contacts 212a close to complete a circuit for energizing the exposure lamp 54. A normally closed set of contacts 2140 open to deenergize the brake 64 and a normally closed set of contacts'216a open to de-energize the copy sheet supply clutch 211. A normally open set of contacts 2l4b close to complete a circuit for energizing the clutch 60 and the original sheet and the copy sheet move in synchronism past the exposure and illumination stations 22 and 20. A normally open set of contacts 216b close to complete a holding circuit together with the original sheet sensing switch 38 in its alternate position for maintaining the relays 212, 214, and 216 energized until the original sheet clears the original sheet sensing switch 38.

When the original sheet and the copy sheet clear the sheet sensing switches 38 and 40, the control circuit 56 returns to the standby condition illustrated except that the exposure lamp S4 is maintained energized for a period of time while the original sheet completes its movement past the illumination station 20. This is accomplished by any suitable means such as the use of a slow release relay for the lamp relay 212. in addition, at the end of the copy making process when the relay 216 is de-energized, a normally closed set of contacts 216c reclose to provide an operating signal for suitable counting and indicating apparatus shown in block form and designated as 217.

In order to condition the machine for reduced size copy making operations, the selector switch 58 is moved by the user from its-illustrated open position to its closed position. When the switch 58 is closed, the drive system 28 is conditioned for moving an original sheet past the illuminating station 20 faster than a copy sheet ismoved past the exposure station 22, and for momentarily holding the original while the copy sheet advancesthereby to center the reduced image on the copy sheet. In addition, the reduced size reproduction lens is moved into position for reduced size copying operations, and the edge exposure lamps 188 and 190 are energized. I i

More specifically, when the switch 58 is closed a circuit is completed for connecting the edge exposure lamps 188 and 190 between the input terminals 200 and 202. in addition, a reduced size operating'relay 218 is energized, and a normally closed set of contacts 218a are opened to disconnect the clutch 60 while a normally open 'set of contacts 218b are closed to energize the clutch 62. As a result, the original sheet drive rollers 30 and 32 commence to rotate at a faster speed than the copy sheet drive rollers 34 and 36.

Energization of the relay 218 also results in closing of a normally open set of contacts 2180 and opening of a normally closed set of contacts 218d so that a circuit is completed through the closed switch 174 for energization of the turret assembly motor 160. The motor is reversible and includes a pair of motor windings 160a and 16% in circuit with a phase lag capacitor 220.

When the motor 160 is energized by connection of the winding l60b to the input terminal 202, the motor shaft 161 is rotated in the direction for moving the lens 130 into position for reduced size copying operations when the abutment 154 reaches the stop 148, and after a predetermined overtravel, the switch 174 opens to deenergize the motor 160 and to energize the brake 176 thereby to clamp the motor shaft 161 in position.

When the relay 218 is energized, a normally open set of contacts 2182 are closed and a normally closed set of contacts 218f are opened in order to disconnect the relay 214 from the circuit and to condition the circuit for operation of the time delay relay 210. The relay 210 includes a time delay adjustment circuit including a variable resistor 222, and its operation is such that when the relay 210 is energized by closure of the copy sheet sensing switch 40, a predetermined time delay period passes after which the normally closed contacts 210a open and a normally open set of contacts 2101) close. The time delay relay 210 staggers the movement of the original and the copy sheet through the machine so that the copy produced on the copy sheet is centered.

After the machine has been placed in standby condition for reduced size copy making conditions by closure of the switch 58, a reduced size copy may be made by inserting an original sheet into the machine until its leading edge operates the original sheet sensing switch 38. When this occurs, the clutch 62 is de-energized and the brake 64 together with the copy sheet supply clutch 211 are energized by a circuit including the normally closed contacts 210a of the time delay relay 210. When a copy sheet is fed from the copy sheet supply enclosure and its leading edge closes the copy sheet sensing switch 40, a circuit is completed for energizing the relays 212, 216 and 210. Energization of the relay 212 completes a circuit for energizing the exposure lamp 54 while energization of the relay 216 deenergizes the copy sheet supply clutch 211. However, since the relay 214 is not energized in reduced copy operation, the brake 64 remains energized through the contacts 210a and the clutch 62 remains de-energized so that the original is' momentarily held stationary while the copy sheet moves into the exposure station 22.

After a predetermined time sufficient to center the copy image on the'copy sheet, the time'delay relay 210 operates and the normally open contacts 210b close to complete a circuit for energization of the clutch 62 while the normally closed contacts 210a open to deenergize the brake 64. At this time the original sheet begins to move into the illumination station 20 at a faster speed than the copy sheet is moving through the exposure station 22, and a reduced size copy is made on the center of the copy sheet. When the sheet sensing switches 38 and 40 are cleared, the relays 212 216 and 210 are deenergized and the machine returns to its standby condition in the manner described previously in connection with full size copying operations.

Return of the machine to the condition for making full size copies is accomplished by reopening the selector switch 58. When this is done, the clutch 62 is deenergized and the clutch 60 is energized; the time delay relay 210 is disconnected and the relay 214 is connected; and the edge exposure lamps 188 and 190 are disconnected. In addition, the normally closed set of contacts 218d are reclosed so that a circuit is completed to the turret motor through the closed switch in order to connect the winding 160a to the input terminal 202 to rotate the turret assembly 126 back 'to its initial position. When the turret assembly reaches its position and when a predetermined overtravel of the motor 160 takes place, the switch 180 reopens as previously described in order to deenergize the motor 160 and to energize the brake 176.

Although the present invention has been described in connection with details of a particular embodiment, those skilled in the art may devise other embodiments and modifications falling within the spirit and scope of the invention. Accordingly, it should be understood that details of the described embodiment do not limit the invention except as set-forth in the following claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A drive system for propelling an original sheet and a copy sheet simultaneously past an illumination station and an exposure station respectively, said drive system comprising first roller means for propelling one of said sheets, a drive motor coupled to said first roller means for rotating said first roller means at a predetermined first speed, second roller means for propelling the other of said sheets, first means for coupling said first and second roller means to cause said first and second roller means to rotate at the same speed, second means for coupling said first and second roller means to cause said second roller means to operate at a different speed than said first roller means, and control means selectively operable for operating one of said first and second coupling means.

2. A drive system for propelling an original sheet and a copy sheet simultaneously past an illumination station and an exposure station respectively, said drive system comprising first roller means for propelling one of said sheets, a drive motor coupled to said first roller means for rotating said first roller means at a predetermined first speed, second roller means for propelling the other of said sheets, first means for coupling said first and second roller means to cause said first and second roller means to rotate at the same speed, second means for coupling said first and second roller means to cause said second roller means to operate at a different speed than said first roller means, and control means selectively operable for operating one of said first and second coupling means,

said first coupling means including a first electric clutch coupled directly between said first and second roller means, said second coupling means including speed reduction means coupled to said first roller means, and a second electric clutch coupled between said speed reduction means and said second roller means.

3. The drive system of claim 2, further comprising an electric'brake connected to said second roller means, said control means including first circuit means for energizing a selected one of said first and second electric clutches thereby to propel the original sheet and copy sheet at selected relative speeds, and second circuit means for deenergizing both said first and second electric clutches and for simultaneously energizing said electric brake thereby to propel one of the sheets and stop the other sheet.

4. For use in an automatic copying machine, a drive one in line pair of copy sheet and original sheet system for propelling an original sheet past an illuminadrive rollers for rotating said copy sheet and tion station and for propelling a copy sheet past an exoriginal sheet drive rollers at said first speed; posure station, said drive system comprising in coma speed reduction shaft for the other in line original bination: 5 sheet drive rollers;

a pair of copy sheet drive rollers disposed on coupling means connected between said shaft and osite side of the e o re ta i d l d one of said original sheet drive rollers for rotating for rotation at the same speed; Said Shaft at a Second p and a drive motor coupled to one of said copy sheet drive a Second Selectively operable clutch connected rollers for rotating said copy sheet drive rollers at a between Said shaft and one of said Original Sheet fi t d; drive rollers for rotating said original sheet drive a pair of original sheet drive rollers in line with said rollers at Said Second p copy sheet drive rollers and disposed on opposite The drive System of claim 4 comprising 3 sides f the illuminating station and coupled f0r brake connected to one of said original sheet drive rolmtation at the Same speed; l5 lers for stopping said original sheet drive rollers.

a first selectively operable clutch connected between 

1. A drive system for propelling an original sheet and a copy sheet simultaneously past an illumination station and an exposure station respectively, said drive system comprising first roller means for propelling one of said sheets, a drive motor coupled to said first roller means for rotating said first roller means at a predetermined first speed, second roller means for propelling the other of said sheets, first means for coupling said first and second roller means to cause said first and second roller means to rotate at the same speed, second means for coupling said first and second roller means to cause said second roller means to operate at a different speed than said first roller means, and control means selectively operable for operating one of said first and second coupling means.
 2. A drive system for propelling an original sheet and a copy sheet simultaneously past an illumination station and an exposure station respectively, said drive system comprising first roller means for propelling one of said sheets, a drive motor coupled to said first roller means for rotating said first roller means at a predetermined first speed, second roller means for propelling the other of said sheets, first means for coupling said first and second roller means to cause said first and second roller means to rotate at the same speed, second means for coupling said first and second roller means to cause said second roller means to operate at a different speed than said first roller means, and control means selectively operable for operating one of said first and second coupling means, said first coupling means including a first electric clutch coupled directly between said first and second roller means, said second coupling means including speed reduction means coupled to said first roller means, and a second electric clutch coupled between said speed reduction means and said second roller means.
 3. The drive system of claim 2, further comprising an electric brake connected to said second roller means, said control means including first circuit means for energizing a selected one of said first and second electric clutches thereby to propel the original sheet and copy sheet at selected relative speeds, and second circuit means for deenergizing both said first and second electric clutches and for simultaneously energizing said electric brake thereby to propel one of the sheets and stop the other sheet.
 4. For use in an automatic copying machine, a drive system for propelling an original sheet past an illumination station and for propelling a copy sheet past an exposure station, said drive system comprising in combination: a pair of copy sheet drive rollers disposed on opposite sides of the exposure station and coupled for rotation at the same speed; a drive motor coupled to one of said copy sheet drive rollers for rotating said copy sheet drive rollers at a first speed; a pair of original sheet drive rollers in line with said copy sheet drive rollers and disposed on opposite sides of the illuminating station and coupled for rotation at the same speed; a first selectively operable clutch connected between one in line pair of copy sheet and original sheet drive rollers for rotating said copy sheet and original sheet drive rollers at said first speed; a speed reduction shaft for the other in line original sheet drive rollers; coupling means connected between said shaft and one of said original sheet drive rollers for rotating said shaft at a second speed; and a second selectively operable clutch connected between said shaft and one of said original sheet drive rollers for rotating said original sheet drive rollers at said second speed.
 5. The drive system of claim 4 further comprising a brake connected to one of said original sheet drive rollers for stopping said original sheet drive rollers. 